Success Story | Water Management

KAESER’s advanced FBS 720 L SFC series rotary screw blower has enabled the Coteau-du-Lac Wastewater Treatment Plant in Canada to enhance the efficiency of its biological treatment process, and achieve immediate energy savings while establishing a foundation for full, synchronised blower system automation in the future.

The Municipal Wastewater Treatment Plant (WWTP) in Coteau-du-Lac, Canada, is responsible for treating over two million cubic metres of wastewater annually, drawn from the city as well as the neighbouring municipality of Les Coteaux.

Once the incoming wastewater has been screened, it enters aerated lagoons where low-pressure air is injected to establish and maintain the dissolved oxygen (DO) levels required for biological treatment. This aeration-driven oxygen supply creates the optimal environment for microorganisms to metabolise and break down the organic matter present in the influent.

The success of this process hinges on maintaining precise DO setpoints, which must be seasonally adjusted to account for fluctuations in environmental conditions such as water temperature and microbial metabolic rates. A reliable supply of low-pressure air - tailored specifically to the operation’s airflow and pressure demands - is therefore critical; even slight variations in air delivery can destabilise microbial activity, resulting in poor treatment and increased operational costs.

The aeration system at the Coteau-du-Lac WWTP relies on a series of blowers to deliver the low-pressure air essential for biological treatment. With one of the facility’s existing rotary lobe blowers reaching the end of its service life, an upgrade was required to ensure continued operational reliability of the entire system.

The primary objective was to achieve immediate efficiency by investing in a high-performance solution designed to deliver significant energy savings from day one. Crucially, the new blower needed to feature advanced control technology, capable of automatically adjusting its speed based on air demand in order to maintain precise dissolved oxygen (DO) level setpoints in the aerated lagoons. This capability is essential for managing seasonal fluctuations, ultimately future-proofing the facility and supporting long-term goals for plant-wide automation and optimisation.

To meet the WWTP’s immediate requirements and support future automation, KAESER recommended the FBS 720 L SFC series rotary screw blower. This ‘plug-and-play’ turnkey solution, provides exceptional performance and low energy consumption, offering savings of up to 35% compared to conventional rotary lobe blowers. Such superior efficiency is maintained across a broad flow rate control range by combining a blower airend featuring energy-saving SIGMA PROFILE rotors with flow-optimised components. When paired with high-efficiency drive motors and a loss-free power transmission system, the unit ensures exceptional operational performance throughout its entire service life.

The FBS 720 L SFC utilises the SIGMA FREQUENCY CONTROL (SFC) to provide precise variable speed control. This integrated frequency converter automatically adjusts the flow rate to match the actual air demand of the process, ensuring the blower operates at peak efficiency even as lagoon conditions fluctuate. Individual operation is managed by the internal SIGMA CONTROL controller, which provides comprehensive monitoring and efficient local control, while allowing the blower to communicate seamlessly with a master control system via various communication interfaces (e.g. ProfiBus, ProfiNet, or Modbus TCP) for fully automated and synchronised operation.

The SIGMA CONTROL controller connects to the SIGMA AIR MANAGER 4.0 (SAM 4.0) master control system via the secure KAESER SIGMA NETWORK or integrated plug-in modules, enabling multiple blowers to be integrated into a single, cohesive network. This connectivity allows for the automated synchronisation of all blowers within the system, where speed and airflow are collectively adjusted to match real-time dissolved oxygen (DO) setpoints. By selecting a solution with these advanced interface options, the Coteau-du-Lac WWTP would effectively future-proof its infrastructure, ensuring a seamless transition to a fully networked and automated aeration system as remaining units are replaced.

The installation of the KAESER FBS 720 L SFC rotary screw blower delivered notable energy cost savings from the start. Impressed with the performance and advanced control capabilities of the KAESER FBS series, as well as the excellent support and responsiveness of the local KAESER team, the facility is now looking to upgrade its remaining aeration blowers with KAESER, continuing its move towards optimising energy consumption and streamlining operations through advanced automation.